The present invention relates generally to a rotating disk storage device and, more particularly, to a rotating disk storage device having an improved actuator arm that is secured through insert molding to a carriage made of a plastic resin.
A magnetic disk drive, as one of applied examples of the rotating disk storage device, generally includes a head disk assembly (hereinafter referred to, in this specification, as an HDA) and a printed circuit board mounted thereon. The HDA is an enclosed structure of a disk enclosure for accommodating in a clean air environment a magnetic disk, an actuator head suspension assembly (hereinafter referred to, in this specification, as an AHSA), a spindle motor, electronic components, and the like. The printed circuit board is mounted with electronic components for controlling operations of the magnetic disk drive and transfer of data.
The AHSA is mounted with a slider, to which a magnetic head for reading and writing data is mounted and which provides an air bearing surface. The AHSA includes an actuator assembly having a carriage arm that pivotally moves about a pivot.
A coil support is formed in part of the carriage arm. The carriage arm holds a voice coil. The coil support is disposed in a magnetic field of a voice coil magnet. The voice coil magnet and the voice coil form a voice coil motor (hereinafter referred to, in this specification, as a VCM) that generates a driving force for pivotally moving the carriage arm.
When the magnetic disk spins, a surface air flow gives the air bearing surface of the slider a lifting force, causing the slider to fly just above the magnetic disk surface. The driving force of the VCM causes the slider to pivotally move about the pivot substantially radially relative to the magnetic disk. While pivotally moving, the slider maintains a position slightly above the magnetic disk surface. The slider thus allows the magnetic head to position at a desired radial location on the disk surface for reading/writing data.
The AHSA of the magnetic disk drive must be capable of accurately controlling positioning of the magnetic head that reads data from and writes data onto the magnetic disk. To achieve this purpose, a pivot bearing assembly that pivotally moves accurately about the pivot is inserted in a pivot opening in the carriage arm.
The carriage arm generally includes the following components. The components are specifically the pivot opening having a fastening function relative to the pivot; an actuator arm having a support function relative to a head suspension assembly (hereinafter referred to, in this specification, as an HSA) mounted with the slider; a mounting surface having a fastening function relative to a flexible cable; and the coil support having a holding function relative to the voice coil. Two actuator arms may, for example, be provided one for the upper and the other for the lower. The two actuator arms are press-fitted into a spacer and insert-molded in a plastic resin with the voice coil. The carriage arm is therefore an assembly including five components of two metal actuator arms, one metal spacer, one voice coil, and one plastic resin carriage.
Improvements are being made to achieve cost reduction by implementing a simple structure and reducing the number of components for the carriage arm that includes the five components to serve the four different functions, while allowing each of these components to perform its intended function.
For example, a first carriage arm is proposed. The first carriage arm is a unitized body that includes five different components of two actuator arms, one spacer, one voice coil, and one carriage. This arrangement is achieved by integrating the carriage with the actuator arms by forming the two actuator arms with a plastic resin.
A second carriage arm is proposed. The second carriage arm is a unitized body including three different components. A metal is formed into a predetermined cross-sectional shape through extrusion molding to make actuator arms and spacer. The extrusion-molded metal is then subjected to a cutting process for cutting each of the two actuator arms to a predetermined thickness. Electric continuity is then established between the actuator arms and the pivot bearing assembly.
Also proposed is a head moving device, in which the number of components used in the carriage arm is reduced to achieve cost reduction (see, for example, Japanese Patent Laid-open No. Hei 03-35482). In this head moving device, two actuator arms are connected together and the connection between the two actuator arms is folded so that the two actuator arms oppose each other to form a single component.